Generating point-in-time copy commands for extents of data

ABSTRACT

Provided are a computer program product, system, and method for generating point-in-time copy commands for extents of data. An establish point-in-time copy command is generated for at least one range of extents in at least one volume in the source storage for a point-in-time copy identifier. The at least one range of extents comprises less than all the extents included in the at least one volume. The establish point-in-time copy command is transmitted to a point-in-time copy manager to cause the point-in-time copy manager to create a point-in-time copy for the copy point-in-time identifier and the at least one range of extents, to generate change recording information indicating each of the at least one range of extents, to copy data in the source storage to be updated as changed data, and to indicate in the change recording information the data that has been updated.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a computer program product, system, andmethod for generating point-in-time copy commands for extents of data.

2. Description of the Related Art

In a storage environment, a storage controller may create point-in-time(“PiT”) copies of a production volume using point-in-time copytechniques, such as the IBM FlashCopy® (FlashCopy is a registeredtrademark of IBM), snapshot, etc. A point-in-time copy replicates datain a manner that appears instantaneous and allows a host to continueaccessing the source volume while actual data transfers to the copyvolume are deferred to a later time. The point-in-time copy appearsinstantaneous because complete is returned to the copy operation inresponse to generating the relationship data structures without copyingthe data from the source to the target volumes. Point-in-time copytechniques typically defer the transfer of the data in the source volumeat the time the point-in-time copy relationship was established to thecopy target volume until a write operation is requested to that datablock on the source volume. Data transfers may also proceed as abackground copy process with minimal impact on system performance. Thepoint-in-time copy relationships that are immediately established inresponse to the point-in-time copy command include a bitmap or otherdata structure indicating the location of blocks in the volume at eitherthe source volume or the copy volume. The point-in-time copy comprisesthe combination of the data in the source volume and the data to beoverwritten by the updates transferred to the target volume.

When an update to a block in the source volume involved in apoint-in-time copy relationship is received, the copy of the track as ofthe point-in-time must be copied to a side file or the target volumebefore the new data for the track is written to the source volume,overwriting the point-in-time copy of the data.

SUMMARY

Provided are a computer program product, system, and method forgenerating point-in-time copy commands for extents of data. An establishpoint-in-time copy command is generated for at least one range ofextents in at least one volume in the source storage for a point-in-timecopy identifier. The at least one range of extents comprises less thanall the extents included in the at least one volume. The establishpoint-in-time copy command is transmitted to a point-in-time copymanager to cause the point-in-time copy manager to create apoint-in-time copy for the copy point-in-time identifier and the atleast one range of extents, to generate change recording informationindicating each of the at least one range of extents, to copy data inthe source storage in the at least one range of extents to be updated aschanged data to the target storage, and to indicate in the changerecording information the data in the at least one range of extents thathas been updated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an embodiment of a storage environment.

FIG. 2 illustrates an embodiment of point-in-time copy information.

FIG. 3 illustrates an embodiment of changed data.

FIG. 4 illustrates an embodiment of an establish point-in-time copycommand.

FIG. 5 illustrates an embodiment of an incremental point-in-time copycommand.

FIG. 6 illustrates an embodiment of operations to generate an establishpoint-in-time copy command.

FIG. 7 illustrates an embodiment of operations to process the establishpoint-in-time copy command to establish a point-in-time copy.

FIG. 8 illustrates an embodiment of operations to generate anincremental point-in-time copy command.

FIGS. 9a and 9b illustrate an embodiment of operations to process theincremental point-in-time copy command to create an incrementalpoint-in-time copy command.

FIG. 10 illustrates an embodiment of operations to process a writerequest.

FIG. 11 illustrates an embodiment of a restore point-in-time copycommand.

FIG. 12 illustrates an embodiment of operations to generate a restorepoint-in-time copy command.

FIG. 13 illustrates an embodiment of operations to process the restorepoint-in-time copy command to restore extents to a previouspoint-in-time.

FIG. 14 illustrates a computing environment in which the components ofFIG. 1 may be implemented.

DETAILED DESCRIPTION

Described embodiments provide techniques for establishing apoint-in-time copy for at least one range of extents comprising a subsetof the extents in a volume to allow a more targeted point-in-time copythat does not include those extents in a volume not of interest to theuser. Described embodiments allow a host to specify various extentranges in at least one volume to a storage controller to participate ina point-in-time copy relationship, such as an incremental FlashCopyrelationship. After an extent level point-in-time copy is established,the extent ranges in the point-in-time copy are monitored for incomingupdates. Updated data in extents in a point-in-time copy are copied tochanged data in a target storage and change recording information isupdated to indicate the data in the extents that have been modified.Further, with described embodiments, the host may modify the ranges ofextents provided for a point-in-time copy.

Described embodiments provide advantages over current point-in-time copysolutions that require the point-in-time copy be performed with respectto an entire volume. Described embodiments optimize point-in-time copyconfiguration for users having files of interest that span a subset ofextents within one or more volumes.

FIG. 1 illustrates an embodiment of a data storage environment having astorage controller 100 managing access to a source storage 102 thatincludes source volumes 104 _(i), such as a production volume used bydifferent host systems 106, and a target storage 108. The volumes 104_(i) are comprised of extents 110 of contiguous tracks. A host system106 includes a point-in-time copy manager program 112 to establishpoint-in-time copies at the storage controller 100, such as FlashCopy,snapshot, etc. The storage controller 100 and hosts 106 may communicateover a network 114.

The storage controller 100 includes a point-in-time copy manager 116 tocreate point-in-time copies of data in the source storage 102, e.g.,FlashCopy, snapshot, etc. When creating a point-in-time copy, thepoint-in-time copy manager 116 generates point-in-time copy information200 on the point-in-time copy created as of a point-in-time. The storagecontroller 100 further includes an operating system 118, including thecode and logic to manage Input/Output (“I/O”) requests to the sourcestorage 102. The operating system 118 may configure the source storage102 and target storage 108 in one or more volumes 104 _(i) and data,such as tracks or logical block addresses (LBAs), grouped in extents.Extents 110 may comprise any grouping of tracks or data units instorage. The point-in-time copy manager 116 may be a copy servicesupplied with the operating system 118.

The target storage 108 includes changed data 300 _(i) comprising datafor tracks in the source storage in extents 110 included in apoint-in-time copy that are updated to provide the updated tracks as ofthe point-in-time before they data is updated.

The storages 102 and 108 may store tracks in a Redundant Array ofIndependent Disks (RAID) configuration where strides of tracks arewritten across multiple storage devices comprising the storages 102 and108. The storages 102 and 108 may each comprise one or more storagedevices known in the art, such as interconnected storage devices, wherethe storage devices may comprise hard disk drives, solid state storagedevice (SSD) comprised of solid state electronics, such as a EEPROM(Electrically Erasable Programmable Read-Only Memory), flash memory,flash disk, Random Access Memory (RAM) drive, storage-class memory(SCM), etc., magnetic storage disk, optical disk, tape, etc.

The network 114 may comprise a network such as one or moreinterconnected Local Area Networks (LAN), Storage Area Networks (SAN),Wide Area Network (WAN), peer-to-peer network, wireless network, etc.

The point-in-time copy manager 116 performs a point-in-time copyoperation that creates a copy of specified extents in a manner thatappears instantaneous and allows a process to continue accessing theextents subject to the point-in-time copy while actual data transfers ofthe copied data are deferred to a later time. The point-in-time copyappears instantaneous because complete is returned to the copy operationin response to generating the relationship data structures, such as thepoint-in-time copy information 200 and change recording information,without copying the data.

The point-in-time copy managers 112, 116 may use the point-in-time copyinformation 200 to restore the source data to different point-in-timesrepresented in the point-in-time copy information 200.

In FIG. 1, the point-in-time copy managers 112 and 116 are shown asimplemented in separate computing systems, a host 106 and storagecontroller 100. In alternative embodiments, the point-in-time copymanagers 112 and 116 may be implemented on a same computer system andoperating system. Still further, the point-in-time copy managers 112 and116 may be modules within a single deployed computer program installedon a single computer system/operating system.

FIG. 2 illustrates an instance of the point-in-time copy information 200_(i), also referred to as a point-in-time copy, which may compriseinformation maintained for the storage controller point-in-time copyinformation 200, and may include a point-in-time copy identifier 202identifying a point-in-time copy and that may be created by the hostpoint-in-time copy manager 112; a point-in-time 204 of the point-in-timecopy 202, such that data for the point-in-time copy information 200 _(i)is consistent as of that point-in-time 204; change recording information206 indicating which data or tracks in the source data 102 has changedsince the point-in-time 204, which may comprise a bitmap having a bitfor each data unit (e.g., track) that is set to one of two valuesindicating the data or track represented by the bit has or has not beenupdated since the point-in-time 204; one or more ranges of extents 208,where each range includes one or more extents 110, and where the extentranges 208 may comprise extents 110 in one or more volumes 104 _(i) andcomprise a subset of the extents 110 in the one or more volumes 104 _(i)in which they are included; and a current flag 210 indicating whetherthe information 200 _(i) is for the current point-in-time copy currentlyrecording information on changes to the tracks in the extents 208 or anarchived point-in-time copy. In alternative embodiments, the currentpoint-in-time copy may be determined by determining the point-in-timecopy instance 200 _(i) having a most current point-in-time 204.

FIG. 3 illustrates an instance of changed data 300 _(i) for modifieddata in the target storage 108 as part of a point-in-time copy, and mayinclude the point-in-time copy identifier 302 providing a uniqueidentifier for the point-in-time copy provided by the host 106 for whichthe changed data is provided; a point-in-time 304 of the changed data308 that is copied over before being updated at the source storage 102;and location 306 of the updated changed data in the source storage 102,such as volume, extent, track; and the changed data 308 as of thepoint-in-time or location of the changed data in the target storage 108as of the point-in-time 304. The changed data 308 may be stored in thetarget storage 108 in a volume, extent and track layout matching that ofthe source volume, extent and track subject to the copy relationship orin a changed data log.

FIG. 4 illustrates an embodiment of a point-in-time copy establishcommand 400 the host point-in-time copy manager 112 sends to the storagecontroller 100 to establish a point-in-time copy 200 _(i) for at leastone range of extents, and includes an establish point-in-time copycommand operation code 402; a unique point-in-time copy identifier 404that may be generated by the host point-in-time copy manager 112; and atleast one range of extents 406 in at least one volume 104 _(i),comprising a subset or less than all the extents 110 in the at least onevolume 104 _(i) including the extents 406.

FIG. 5 illustrates an embodiment of an incremental point-in-time copycommand 500 the host point-in-time copy manager 112 generates to createan additional point-in-time copy for the point-in-time copy identifierpreviously the subject of a point-in-time copy establish command 400 orprevious incremental point-ion-time copy command 500. The incrementalpoint-in-time copy command 500 may include an incremental point-in-timecopy command operation code 502; a point-in-time copy identifier 504used to uniquely identify a point-in-time copy; and extent ranges 506 ofat least one extent of tracks, where the extent ranges 506 may comprisea modification to the extent ranges 406 in the establish command 400 orin a previous incremental point-in-time copy command 500. The extentranges 506 may remove or add extents to the extent ranges 208 previouslyset for the current point-in-time copy 200 _(i) for the point-in-timecopy identifier. Alternatively, the extent ranges 506 may indicate thatthere is no change to the current extents associated with thepoint-in-time copy identifier 504. In such case, the incrementalpoint-in-time copy command 500 is used to create a new point-in-timecopy for a new point-in-time and cause archiving of the currentpoint-in-time copy to allow for use for restoring data.

In FIGS. 4 and 5, the host point-in-time copy manager 112 may create theunique point-in-time copy identifier 404, 504 to use to establish apoint-in-time copy as associated with one or more extents of a volume,less than a volume, to subject to a copy relationship, and then use thatsame point-in-time copy identifier to initiate an additionalpoint-in-time copy or incremental copy and/or change the extents subjectto the point-in-time copy identified by the point-in-time copyidentifier. In an alternative embodiment, the point-in-time copyidentifier 504 may be generated by a different component in the host 106or the storage controller 100.

FIG. 6 illustrates an embodiment of operations performed by the hostpoint-in-time copy manager 112 to generate a point-in-time copyestablish command 400. Upon initiating (at block 600) an operation togenerate an establish point-in-time copy command 400, the hostpoint-in-time copy manager 112 generates (at block 602) a uniquepoint-in-time copy identifier 404. The host point-in-time copy manager112 generates (at block 604) an establish point-in-time copy command 400including the establish point-in-time copy operation code 402, thegenerlated point-in-time copy identifier 404, and a range of extents 406to include in the point-in-time copy. The generated establishpoint-in-time copy command 400 is sent (at block 606) to the storagecontroller 100.

FIG. 7 illustrates an embodiment of operations performed by the storagecontroller 100 point-in-time copy manager 116 to process a receivedestablish point-in-time copy command 400. Upon receiving (at block 700)the command 400, the point-in-time copy manager 116 generates (at block702) change recording information 206 indicating the tracks in each ofthe at least one range of extents 406 indicated in the receivedestablish command 400. The change recording information 206 may onlyinclude bits or information for the specified extents 406 and notnon-specified extents in the at least one volume including the extents406. In this way, the change recording information 206 conserves spaceby only providing information, or including bits, for those extents 406subject to the point-in-time copy. The point-in-time copy manager 116generates point-in-time copy information 200 _(i) indicating thepoint-in-time copy identifier 402 in the received establish command 400,a current point-in-time 204 at which the copy is being created, thegenerated change recording information 206, and the at least one rangeof extents 208 indicated in the establish command 400. The current flag210 is set (at block 706) to indicate the generated point-in-time copyinformation 200 _(i) is the current point-in-time copy. As mentionedother mechanisms than a current flag 210 may be used to indicate acurrent point-in-time copy.

FIG. 8 illustrates an embodiment of the host point-in-time copy manager112 to generate an incremental point-in-time copy command 500. Uponinitiating (at block 800) an operation to generate an incrementalpoint-in-time copy command 500 for an existing point-in-time copyidentifier, the host point-in-time copy manager 112 determines (at block802) the unique point-in-time copy identifier for which the incrementalcopy is being generated. The point-in-time copy manager 112 receives (atblock 804) indication to not modify the range of extents in thepoint-in-time copy or indication of a modified range of extents for thepoint-in-time copy identified by the determined point-in-time copyidentifier. The host point-in-time copy manager 112 generates (at block806) an incremental point-in-time copy command 500 indicating theincremental point-in-time copy operation code 502, the determinedpoint-in-time copy identifier 504, and in field 506 either the indicatedmodified range of extents to modify or indication of no range of extentsif the range of extents in the point-in-time copy for the point-in-timecopy identifier 504 is not to be modified and remain unchanged. Thegenerated incremental point-in-time copy command 500 is sent (at block808) to the storage controller 100 to process.

FIGS. 9a and 9b illustrate an embodiment of operations performed by thepoint-in-time copy manager 116 to process an incremental point-in-timecopy command 500 received from a host 106 to establish a new incrementalpoint-in-time copy for the point-in-time copy identifier used in aprevious establish command 400 or previous incremental point-in-timecopy command 500. Upon receiving (at block 900) the incrementalpoint-in-time copy command 500 including the point-in-time copyidentifier 504 and optionally modified extent ranges 506, if (at block902) there is no point-in-time copy information 200 _(i) for thepoint-in-time copy identifier 504 in the command 500, an error returned(at block 904) to the host 106 initiating the received command 500. If(at block 902) there is point-in-time copy information 200 _(i) for thepoint-in-time copy identifier 504, then the point-in-time copy manager116 saves (at block 906) the current point-in-time copy information 200_(i) and the change recording information 206 in the source storage 102,target storage 108 or other location.

If (at block 908) the command 500 does not include modified extentranges 506, then the point-in-time copy manager 116 makes (at block 910)a copy of the saved change recording information 206 _(i) for theprevious point-in-time 204 _(i) to use as the new change recordinginformation 206 _(i+1) for the next point-in-time 204 _(i+1). If (atblock 908) the command 500 does include modified extent ranges 506, thenthe point-in-time copy manager 116 generates (at block 912) new changerecording information 206 _(i+1) indicating each of the at least onerange of extents 506 in the command 500. From blocks 910 or 912, forthose tracks in extents in the change recording information 206 _(i) forthe current point-in-time 204 _(i) carried over to the new changerecording information 206 _(i+1), the point-in-time copy manager 116copies (at block 914) the indicated values for the tracks from thecurrent change recording information 206 _(i) to the new changerecording information 206 _(i+1). The point-in-time copy manager 116generates (at block 916) point-in-time copy information 200 _(i+1) forthe new point-in-time copy indicating the point-in-time copy identifier504 in the incremental command 500, a new point-in-time 204 _(i+1) atwhich the copy is being created, the new change recording information206 _(i+1), the at least one range of extents 208 _(i+1) indicated inthe incremental command 500 or the previous used range of extents, andsets the current flag 210 to indicate the new generated point-in-timecopy information 200 _(i+1) as current. The current flag 210 for theprevious point-in-time copy 200 _(i) may be reset to indicate that theprevious point-in-time copy 200 _(i) is not the most currentpoint-in-time copy. Control then proceeds to block 918 in FIG. 9 b.

At block 918, if the modified at least one range of extents 506 removesextents from the extents 208 _(i) previous point-in-time copy 200 _(i),then the point-in-time copy manager 116 copies (at block 920) data inthe source storage 102 for the at least one extent being removed to thetarget storage 108 and associates the copied data as changed data 300_(i) for the at least one extent being removed with the savedpoint-in-time copy 304, and the location 306 in the source storage 102from which the data is copied. The point-in-time copy manager 116indicates (at block 922) in the saved change recording information 206_(i) the data for the at least one extent being removed as modified. If(at block 918) extents are not being removed in the modified extents 506with the incremental command 500 (from the no branch of block 918) orafter block 922, the point-in-time copy manager 116 switches over (atblock 924) to use the new generated point-in-time copy 200 _(i+1) andnew change recording information 206 _(i+1) as the current point-in-timecopy and current change recording information. In alternativeembodiments, the operations of blocks 918, 920, and 922 may not beperformed to not save the data with the current point-in-time copy 200_(i) for extents being removed in the modified extents 208 _(i+1) in thenew point-in-time copy 200 _(i+1)

With the operations of FIGS. 8, 9 a and 9 b, the ranges of extents beingmonitored for a point-in-time copy identified by point-in-time copyidentifier may be modified to specify a different range of extents forthe point-in-time copy of the copy identifier, which ranges of extentsare a subset of the one or more volumes including the extents. Theincremental point-in-time copy command 500 further causes the storagecontroller 100 to create a new point-in-time copy at a new point-in-timefor purposes of creating an additional incremental backup.

FIG. 10 illustrates an embodiment of operations performed by theoperating system 118 to handle a write request to the source storage102. Upon receiving (a block 1000) a write from a host 106 to one of thetracks in an extent 110 to update data, a determination is made (atblock 1002) as to whether one of the current point-in-time copies 200_(i) includes a range of extents 208 including the data to update. Ifnot, then the write is performed (at block 1004) to update the data. If(at block 1002) there is a current point-in-time copy 200 _(i)associated with at least one range of extents including the data toupdate, then a loop of operations is performed at block 1006 through1012 for each of the current point-in-time copies 200 including a rangeof extents 208 having the data to update. At block 1008, the operatingsystem 118 copies the current point-in-time data in the extents in thesource storage to be updated to changed data 300 _(i) in the targetstorage 108 indicating the point-in-time copy identifier 302 of thepoint-in-time copy, the current point-in-time 304, and the location 306of the updated data in the source storage 102. The operating system 118or other component indicates (at block 1010) in the change recordinginformation 206 for the point-in-time copy the data in the at least onerange of extents that has been updated. After copying over the data tobe updated on the write, the update is applied (at block 1014). Afterwriting the data at block 1004 or 1014, complete is returned (at block1016) to the write.

FIG. 11 illustrates an embodiment of a restore point-in-time copycommand 1100 to restore source extents 110 as of a point-in-time for apoint-in-time copy 200 _(i), and includes a restore command operationcode 1102; a unique point-in-time copy identifier 1104; and apoint-in-time copy 1106 for the point-in-time copy identifier 1104 torestore. that may be generated by the host point-in-time copy manager112.

FIG. 12 illustrates an embodiment of the host point-in-time copy manager112 to generate a restore point-in-time copy command 1100. Uponinitiating (at block 1200) an operation to generate a restorepoint-in-time copy for an existing point-in-time copy identifier 202,the host point-in-time copy manager 112 determines (at block 1202) theunique point-in-time copy identifier 202 and a point-in-time copy 200_(i) for the point-in-time copy identifier 202 to restore. The hostpoint-in-time copy manager 112 generates (at block 1204) a restorepoint-in-time copy command 1100 indicating the restore point-in-timecopy operation code 1102, the determined point-in-time copy identifier202 in field 1104, and the determined point-in-time copy 200 _(i) infield 1106 to restore. The generated restore point-in-time copy command1100 is sent (at block 1206) to the storage controller 100 to process.

With the operations of FIGS. 6, 8, and 12, the host point-in-time copymanager 112 may generate a graphical user interface in which the usermay select a point-in-time copy identifier and extents for the establish400 and incremental 500 point-in-time copy commands, and select thepoint-in-time copy identifier and point-in-time copy for a restorepoint-in-time copy command 1100. Alternatively, a user may code a scriptcommand with determined point-in-time copy identifier, extents, and/orpoint-in-time copy for the commands 400, 500, 1100 to then transmit tothe storage controller 100.

FIG. 13 illustrates an embodiment of operations performed by thepoint-in-time copy managers 112 and 116 to restore the source storage toa point-in-time for a point-in-time copy identifier. The hostpoint-in-time copy manager 112 may use a user interface to determineavailable point-in-time copies for ranges of extents to restore. Uponreceiving (at block 1300) from the host 106 a restore point-in-time copycommand 1100, the storage controller point-in-time copy manager 116accesses (at block 1302) the point-in-time copy information 200 _(i) andthe change recording information 206 _(i) for the point-in-time copyidentifier 1104 and point-in-time copy 1106 indicated in the receivedrestore command 1100 to restore. For all the data indicated as modifiedin the accessed change recording information 206 _(i) for thepoint-in-time copy 200 _(i) and point-in-time copy identifier torestore, the point-in-time copy manager 116 copies (at block 1304) thechanged data 300 _(i) in the target storage 108 associated with theselected point-in-time copy identifier 302 and point-in-time 304 torestore to the locations in the source storage 102 indicated in thelocation 306 in the changed data 300 _(i) to return the extents 110 inthe source storage 102 to a state as of the restore point-in-time copy1106.

Described embodiments provide techniques for a host system to specify toa storage controller selected extents of a volume, comprising less thanall the extents in the volume, to include in a point-in-time copy. Inthis way, computational and storage resources are conserved by limitingthe point-in-time copy to only those extents of data in a volume inwhich the user is interested in copying, not having to subject theentire volume to the point-in-time copy. A point-in-time copy isestablished for at least one range of extents in at least one volume fora point-in-time copy identifier, which may be generated and provided bythe host initiating the point-in-time copy. Change recording informationis generated indicating each of the at least one range of extents lessthan all of the extents in the at least one volume. Upon receiving anupdate to data in the at least one range of extents in the point-in-timecopy, the data in the source storage in the at least one range ofextents to be updated is copied as changed data to the target storageand indication is made in the change recording information for thepoint-in-time copy the data in the at least one range of extents thathas been updated.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Java, Smalltalk, C++ or the like,and conventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

The computational components of FIG. 1, including the storage controller100 and host 106 may be implemented in one or more computer systems,such as the computer system 1402 shown in FIG. 14. Computersystem/server 1402 may be described in the general context of computersystem executable instructions, such as program modules, being executedby a computer system. Generally, program modules may include routines,programs, objects, components, logic, data structures, and so on thatperform particular tasks or implement particular abstract data types.Computer system/server 1402 may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

As shown in FIG. 14, the computer system/server 1402 is shown in theform of a general-purpose computing device. The components of computersystem/server 1402 may include, but are not limited to, one or moreprocessors or processing units 1404, a system memory 1406, and a bus1408 that couples various system components including system memory 1406to processor 1404. Bus 1408 represents one or more of any of severaltypes of bus structures, including a memory bus or memory controller, aperipheral bus, an accelerated graphics port, and a processor or localbus using any of a variety of bus architectures. By way of example, andnot limitation, such architectures include Industry StandardArchitecture (ISA) bus, Micro Channel Architecture (MCA) bus, EnhancedISA (EISA) bus, Video Electronics Standards Association (VESA) localbus, and Peripheral Component Interconnects (PCI) bus.

Computer system/server 1402 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 1402, and it includes both volatileand non-volatile media, removable and non-removable media.

System memory 1406 can include computer system readable media in theform of volatile memory, such as random access memory (RAM) 1410 and/orcache memory 1412. Computer system/server 1402 may further include otherremovable/non-removable, volatile/non-volatile computer system storagemedia. By way of example only, storage system 1413 can be provided forreading from and writing to a non-removable, non-volatile magnetic media(not shown and typically called a “hard drive”). Although not shown, amagnetic disk drive for reading from and writing to a removable,non-volatile magnetic disk (e.g., a “floppy disk”), and an optical diskdrive for reading from or writing to a removable, non-volatile opticaldisk such as a CD-ROM, DVD-ROM or other optical media can be provided.In such instances, each can be connected to bus 1408 by one or more datamedia interfaces. As will be further depicted and described below,memory 1406 may include at least one program product having a set (e.g.,at least one) of program modules that are configured to carry out thefunctions of embodiments of the invention.

Program/utility 1414, having a set (at least one) of program modules1416, may be stored in memory 1406 by way of example, and notlimitation, as well as an operating system, one or more applicationprograms, other program modules, and program data. Each of the operatingsystem, one or more application programs, other program modules, andprogram data or some combination thereof, may include an implementationof a networking environment. The components of the computer 1402 may beimplemented as program modules 1416 which generally carry out thefunctions and/or methodologies of embodiments of the invention asdescribed herein. The systems of FIG. 1 may be implemented in one ormore computer systems 1402, where if they are implemented in multiplecomputer systems 1402, then the computer systems may communicate over anetwork.

Computer system/server 1402 may also communicate with one or moreexternal devices 1418 such as a keyboard, a pointing device, a display1420, etc.; one or more devices that enable a user to interact withcomputer system/server 1402; and/or any devices (e.g., network card,modem, etc.) that enable computer system/server 1402 to communicate withone or more other computing devices. Such communication can occur viaInput/Output (I/O) interfaces 1422. Still yet, computer system/server1402 can communicate with one or more networks such as a local areanetwork (LAN), a general wide area network (WAN), and/or a publicnetwork (e.g., the Internet) via network adapter 1424. As depicted,network adapter 1424 communicates with the other components of computersystem/server 1402 via bus 1408. It should be understood that althoughnot shown, other hardware and/or software components could be used inconjunction with computer system/server 1402. Examples, include, but arenot limited to: microcode, device drivers, redundant processing units,external disk drive arrays, RAID systems, tape drives, and data archivalstorage systems, etc.

The terms “an embodiment”, “embodiment”, “embodiments”, “theembodiment”, “the embodiments”, “one or more embodiments”, “someembodiments”, and “one embodiment” mean “one or more (but not all)embodiments of the present invention(s)” unless expressly specifiedotherwise.

The terms “including”, “comprising”, “having” and variations thereofmean “including but not limited to”, unless expressly specifiedotherwise.

The enumerated listing of items does not imply that any or all of theitems are mutually exclusive, unless expressly specified otherwise.

The terms “a”, “an” and “the” mean “one or more”, unless expresslyspecified otherwise.

Devices that are in communication with each other need not be incontinuous communication with each other, unless expressly specifiedotherwise. In addition, devices that are in communication with eachother may communicate directly or indirectly through one or moreintermediaries.

A description of an embodiment with several components in communicationwith each other does not imply that all such components are required. Onthe contrary a variety of optional components are described toillustrate the wide variety of possible embodiments of the presentinvention.

When a single device or article is described herein, it will be readilyapparent that more than one device/article (whether or not theycooperate) may be used in place of a single device/article. Similarly,where more than one device or article is described herein (whether ornot they cooperate), it will be readily apparent that a singledevice/article may be used in place of the more than one device orarticle or a different number of devices/articles may be used instead ofthe shown number of devices or programs. The functionality and/or thefeatures of a device may be alternatively embodied by one or more otherdevices which are not explicitly described as having suchfunctionality/features. Thus, other embodiments of the present inventionneed not include the device itself.

The foregoing description of various embodiments of the invention hasbeen presented for the purposes of illustration and description. It isnot intended to be exhaustive or to limit the invention to the preciseform disclosed. Many modifications and variations are possible in lightof the above teaching. It is intended that the scope of the invention belimited not by this detailed description, but rather by the claimsappended hereto. The above specification, examples and data provide acomplete description of the manufacture and use of the composition ofthe invention. Since many embodiments of the invention can be madewithout departing from the spirit and scope of the invention, theinvention resides in the claims herein after appended.

What is claimed is:
 1. A computer program product for generating apoint-in-time copy of data at a source storage to a target storage,wherein the computer program product comprises a computer readablestorage medium having program instructions embodied therewith, theprogram instructions executable by a processor to cause operations, theoperations comprising: generating an establish point-in-time copycommand including at least one range of extents in at least one volumein the source storage and a point-in-time copy identifier, wherein theat least one range of extents comprises less than all extents includedin the at least one volume; and transmitting the establish point-in-timecopy command to a point-in-time copy manager to cause the point-in-timecopy manager to create a point-in-time copy identified by thepoint-in-time copy identifier in the establish point-in-time copycommand and for the at least one range of extents, to generate changerecording information only indicating the at least one range of extentsindicated in the point-in-time copy establish command, to copy data inthe source storage in the at least one range of extents to be updated aschanged data to the target storage, and to indicate, in the changerecording information, the data in the at least one range of extentsthat has been updated.
 2. The computer program product of claim 1,wherein the operations further comprise: generating the point-in-timecopy identifier to include in the establish point-in-time copy command;and receiving user selection of the at least one range of extents toinclude in the establish point-in-time copy command.
 3. The computerprogram product of claim 1, wherein the computer program product isdeployed in a host system and the point-in-time copy manager is deployedin a storage controller managing access to the source and the targetstorages, and wherein the host system and the storage controllercommunicate over a network.
 4. The computer program product of claim 1,wherein the at least one range of extents comprises a first at least onerange of extents, wherein the point-in-time copy comprises a firstpoint-in-time copy, wherein the change recording information comprises afirst change recording information, and wherein the operations furthercomprise: generating an incremental point-in-time copy commandindicating the point-in-time copy identifier and a second at least onerange of extents having a different set of extents than in the first atleast one range of extents; and transmitting the incrementalpoint-in-time copy command to the point-in-time copy manager to causethe point-in-time copy manager to create a second point-in-time copy forthe point-in-time copy identifier and the second at least one range ofextents and generate second change recording information indicating thesecond at least one range of extents, wherein the point-in-time copymanager switches to using the second change recording information toindicate data in the second at least one range of extents in the sourcestorage that is modified for the second point-in-time copy.
 5. Thecomputer program product of claim 1, wherein the point-in-time copycomprises a first point-in-time copy, wherein the change recordinginformation comprises first change recording information, and whereinthe operations further comprise: generating an incremental point-in-timecopy command indicating the point-in-time copy identifier; andtransmitting the incremental point-in-time copy command to thepoint-in-time copy manager to cause the point-in-time copy manager tocreate a second point-in-time copy for the point-in-time copy identifierand the at least one range of extents and generate second changerecording information indicating for the point-in-time copy identifierindicating the at least one range of extents, wherein the point-in-timecopy manager switches to using the second change recording informationto indicate data in the at least one range of extents in the sourcestorage that is modified for the second point-in-time copy.
 6. Thecomputer program product of claim 1, wherein the operations furthercomprise: generating a restore command indicating the point-in-time copyidentifier and a selected point-in-time copy of a plurality ofpoint-in-time copies associated with the point-in-time copy identifier;and transmitting the restore command to the point-in-time copy managerto cause the point-in-time copy manager to use change recordinginformation associated with the selected point-in-time copy to restoredata at the source storage to a point-in-time as of the selectedpoint-in-time copy.
 7. The computer program product of claim 6, whereinthe operations further comprise: providing information on a plurality ofpoint-in-time copy identifiers, wherein each of the point-in-time copyidentifiers is associated with at least one point-in-time copy for atleast one range of extents in the source storage less than all theextents in the source storage; and receiving selection of thepoint-in-time copy identifier and a point-in-time copy associated withthe selected point-in-time copy identifier, wherein the selectedpoint-in-time copy identifier and the selected point-in-time copy areindicated in the restore command.
 8. A system for generating apoint-in-time copy of data at a source storage to a target storage,comprising: a processor; and a computer readable storage medium havingprogram instructions executed by the processor to perform operations,the operations comprising: generating an establish point-in-time copycommand including at least one range of extents in at least one volumein the source storage and a point-in-time copy identifier, wherein theat least one range of extents comprises less than all extents includedin the at least one volume; and transmitting the establish point-in-timecopy command to a point-in-time copy manager to cause the point-in-timecopy manager to create a point-in-time copy identified by thepoint-in-time copy identifier in the establish point-in-time copycommand and for the at least one range of extents, to generate changerecording information only indicating the at least one range of extentsindicated in the point-in-time copy establish command, to copy data inthe source storage in the at least one range of extents to be updated aschanged data to the target storage, and to indicate, in the changerecording information, the data in the at least one range of extentsthat has been updated.
 9. The system of claim 8, wherein the operationsfurther comprise: generating the point-in-time copy identifier toinclude in the establish point-in-time copy command; and receiving userselection of the at least one range of extents to include in theestablish point-in-time copy command.
 10. The system of claim 8, whereinthe system comprises a host system and the point-in-time copy manager isdeployed in a storage controller managing access to the source and thetarget storages, and wherein the host system and the storage controllercommunicate over a network.
 11. The system of claim 8, wherein the atleast one range of extents comprises a first at least one range ofextents, wherein the point-in-time copy comprises a first point-in-timecopy, wherein the change recording information comprises a first changerecording information, and wherein the operations further comprise:generating an incremental point-in-time copy command indicating thepoint-in-time copy identifier and a second at least one range of extentshaving a different set of extents than in the first at least one rangeof extents; and transmitting the incremental point-in-time copy commandto the point-in-time copy manager to cause the point-in-time copymanager to create a second point-in-time copy for the point-in-time copyidentifier and the second at least one range of extents and generatesecond change recording information indicating the second at least onerange of extents, wherein the point-in-time copy manager switches tousing the second change recording information to indicate data in thesecond at least one range of extents in the source storage that ismodified for the second point-in-time copy.
 12. The system of claim 8,wherein the point-in-time copy comprises a first point-in-time copy,wherein the change recording information comprises first changerecording information, and wherein the operations further comprise:generating an incremental point-in-time copy command indicating thepoint-in-time copy identifier; and transmitting the incrementalpoint-in-time copy command to the point-in-time copy manager to causethe point-in-time copy manager to create a second point-in-time copy forthe point-in-time copy identifier and the at least one range of extentsand generate second change recording information indicating for thepoint-in-time copy identifier indicating the at least one range ofextents, wherein the point-in-time copy manager switches to using thesecond change recording information to indicate data in the at least onerange of extents in the source storage that is modified for the secondpoint-in-time copy.
 13. The system of claim 8, wherein the operationsfurther comprise: generating a restore command indicating thepoint-in-time copy identifier and a selected point-in-time copy of aplurality of point-in-time copies associated with the point-in-time copyidentifier; and transmitting the restore command to the point-in-timecopy manager to cause the point-in-time copy manager to use changerecording information associated with the selected point-in-time copy torestore data at the source storage to a point-in-time as of the selectedpoint-in-time copy.
 14. The system of claim 13, wherein the operationsfurther comprise: providing information on a plurality of point-in-timecopy identifiers, wherein each of the point-in-time copy identifiers isassociated with at least one point-in-time copy for at least one rangeof extents in the source storage less than all the extents in the sourcestorage; and receiving selection of the point-in-time copy identifierand a point-in-time copy associated with the selected point-in-time copyidentifier, wherein the selected point-in-time copy identifier and theselected point-in-time copy are indicated in the restore command.
 15. Amethod for forming a point-in-time copy of data at a source storage to atarget storage, comprising: generating an establish point-in-time copycommand including at least one range of extents in at least one volumein the source storage and a point-in-time copy identifier, wherein theat least one range of extents comprises less than all extents includedin the at least one volume; and transmitting the establish point-in-timecopy command to a point-in-time copy manager to cause the point-in-timecopy manager to create a point-in-time copy identified by thepoint-in-time copy identifier in the establish point-in-time copycommand and for the at least one range of extents, to generate changerecording information only indicating the at least one range of extentsindicated in the point-in-time copy establish command, to copy data inthe source storage in the at least one range of extents to be updated aschanged data to the target storage, and to indicate, in the changerecording information, the data in the at least one range of extentsthat has been updated.
 16. The method of claim 15, wherein theoperations further comprise: generating the point-in-time copyidentifier to include in the establish point-in-time copy command; andreceiving user selection of the at least one range of extents to includein the establish point-in-time copy command.
 17. The method of claim 15,wherein the method is implemented in a host system and the point-in-timecopy manager is deployed in a storage controller managing access to thesource and the target storages, and wherein the host system and thestorage controller communicate over a network.
 18. The method of claim15, wherein the at least one range of extents comprises a first at leastone range of extents, wherein the point-in-time copy comprises a firstpoint-in-time copy, wherein the change recording information comprises afirst change recording information, further comprising: generating anincremental point-in-time copy command indicating the point-in-time copyidentifier and a second at least one range of extents having a differentset of extents than in the first at least one range of extents; andtransmitting the incremental point-in-time copy command to thepoint-in-time copy manager to cause the point-in-time copy manager tocreate a second point-in-time copy for the point-in-time copy identifierand the second at least one range of extents and generate second changerecording information indicating the second at least one range ofextents, wherein the point-in-time copy manager switches to using thesecond change recording information to indicate data in the second atleast one range of extents in the source storage that is modified forthe second point-in-time copy.
 19. The method of claim 15, wherein thepoint-in-time copy comprises a first point-in-time copy, wherein thechange recording information comprises first change recordinginformation, further comprising: generating an incremental point-in-timecopy command indicating the point-in-time copy identifier; andtransmitting the incremental point-in-time copy command to thepoint-in-time copy manager to cause the point-in-time copy manager tocreate a second point-in-time copy for the point-in-time copy identifierand the at least one range of extents and generate second changerecording information indicating for the point-in-time copy identifierindicating the at least one range of extents, wherein the point-in-timecopy manager switches to using the second change recording informationto indicate data in the at least one range of extents in the sourcestorage that is modified for the second point-in-time copy.
 20. Themethod of claim 15, further comprising: generating a restore commandindicating the point-in-time copy identifier and a selectedpoint-in-time copy of a plurality of point-in-time copies associatedwith the point-in-time copy identifier; and transmitting the restorecommand to the point-in-time copy manager to cause the point-in-timecopy manager to use change recording information associated with theselected point-in-time copy to restore data at the source storage to apoint-in-time as of the selected point-in-time copy.
 21. The method ofclaim 20, further comprising: providing information on a plurality ofpoint-in-time copy identifiers, wherein each of the point-in-time copyidentifiers is associated with at least one point-in-time copy for atleast one range of extents in the source storage less than all theextents in the source storage; and receiving selection of thepoint-in-time copy identifier and a point-in-time copy associated withthe selected point-in-time copy identifier, wherein the selectedpoint-in-time copy identifier and the selected point-in-time copy areindicated in the restore command.